Objective is the delineation of early signs of an anti-neoplastic response in mammalian cells in culture or in vivo (murine leukemic systems). Specific lines of research involve: 1. A study of early effects of anti-tumor agents on DNA synthesis and DNA degradation. 2. A study of drug effects on cell surface properties, e.g., electrophoretic mobility, permeability barriers, rates of synthesis of cell-surface protein and glycoprotein. 3. Screening of new agents available in limited quantity using procedures described above. Suitable procedures can then be applied to assess early effects on chemotherapy in man to provide physicians with information concerning probable success of individual therapy programs.